The invention relates to a triangular swinging arm for wheel suspensions of motor vehicles, in particular passenger vehicles, said triangular swinging arm being supported against the bodywork via a bearing spring and being constructed of two mutually angled arms, which are each provided with articulated mountings on the bodywork and one of which forms a supporting arm and is connected in articulated fashion in the vicinity of the wheel to the other arm, on which the wheel carrier is articulated.
Triangular swinging arms in the form of essentially rigid triangular swinging arms as well as of nonintegral design are known. In their forms as hitherto known, both designs are affected by fundamental disadvantages.
With regard to the longitudinal spring action, i.e. with regard to loads in the longitudinal direction of the vehicle, the fulcrum of the swinging arm in the case of essentially rigid triangular swinging arms is determined by the hardness of the customarily resilient articulated mounting points on the bodywork and is in general in the region between these articulated mounting points. Taking into consideration acceptable bearing loads, the possible longitudinal spring action is relatively small and, in conjunction with the track rod position, which is in general determined by other structural conditions, tracking errors due to the kinematic elasticity are unavoidable.
For an essentially rigid triangular swinging arm (German Published Unexamined Pat. Application - DE-OS-No. 2,305,449), it is known that such can be constructed from two rigidly connected arms, one of which forks in the direction of the other and is rigidly connected to the other arm via its two fork ends. Compared to swinging arms constructed using sheet metal welding, this makes possible a slimmer, space-saving construction and greater freedom of construction.
In the case of triangular swinging arms of nonintegral design, of the type assumed at the outset to be known, the nonintegral design results in greater restrictions as regards the position of the spring, if the spring is to be supported on the triangular swinging arm, since the force of the spring must run through the line of action of the respective swinging arm supporting it. This in turn imposes considerable restrictions on this spring-carrying swinging arm as regards the position of its articulated mounting points and hence restrictions on the freedom of construction.
An object of the invention is to further develop a triangular swinging arm of the type mentioned at the outset such that, on the one hand, the freedom of construction as regards the arrangement of the spring is the same as that in the case of rigid triangular swinging arms but that, on the other hand, the advantages of nonintegral triangular swinging arms as regards the longitudinal spring action are retained.
According to the invention, this is achieved by the fact that the supporting arm carries the spring and is additionally supported yieldingly against the other arm in a manner laterally offset with respect to the connecting line between its articulated joints on the other arm and bodywork.
In this type of design, the spring can be situated outside the line of action between the articulated joints of the supporting arm, since the resulting moment about the line of action is taken up by the additional support relative to the other arm, said support being outside the line of action. Great freedom in the design of the supporting arm is thereby obtained and, as a result, also with regard to the arrangement of the spring. However, the fundamental advantage of the nonintegral design in respect of the kinematic elasticity behaviour of the axle is retained as well, and an adequate longitudinal spring action can be achieved. Even in the case of structural limitations with regard to the position of the track rod, a triangular swinging arm of this kind thus permits the realization of desired tracking changes.
A preferred embodiment of the solution according to the invention consists in that the supporting arm extends essentially in the longitudinal direction of the vehicle. The arm supporting the supporting arm, in contrast, has a more transversely directed extension. This is favourable in particular for front wheels.
However, within the scope of the invention it is also contemplated to arrange the supporting arm and the arm supporting the latter in a reversed arrangement, which would, for example, be of advantage for rear wheels.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.